Manufacturing method for semiconductor device, mounting method of semiconductor device, semiconductor device, and inspecting method of semiconductor device

ABSTRACT

A manufacturing method for a semiconductor device using a wire bonding method using a metal wire. In the wire bonding method, an impact load applied when a metal ball formed at the tip of the metal wire by electric discharge is brought into contact with a terminal electrode of a semiconductor device is smaller than a static load applied after the metal ball is brought into contact with the terminal electrode. The method makes it possible to prevent an element or wiring from being damaged while securing the pressure necessary for bonding the metal ball to the terminal electrode even when the terminal electrode is placed on the element or the wiring.

FIELD OF THE INVENTION

[0001] The present invention relates to a manufacturing method and amounting method for a semiconductor device, which are capable of beingperformed even in a case where a terminal electrode (pad) for bonding isplaced on an element or wiring.

BACKGROUND OF THE INVENTION

[0002] Recently, as portable type electronic equipment has becomesmaller and has had a higher performance, a semiconductor device, etc.has been required to have a small size and high performance. In order tomeet these requirements, it is necessary to increase the number ofterminal pins, to reduce the pitch or to make an area arrangement. Inthis case, however, there is a limit for reducing the pitch. In order tofurther reduce the pitch, it is important to mount a terminal electrodeon an element or wiring as well.

[0003] According to such a mounting, when a bump is formed or mounted onthe terminal electrode provided at the semiconductor side, if extremelyhigh pressure is applied, the element inside the semiconductor devicemay be destroyed or cracks may occur in an insulating layer. Thus, anelectric current leak occurs between the insulating layer and thewiring. For example, in a technique using a wire boding method, theimpact load may damage the element or the wiring. Therefore, a techniquewhere a terminal electrode is provided on the element or the wiring aswell has not been established. Therefore, when the wire bonding methodis used, it is necessary to form a terminal electrode outside theelement or the wiring. Moreover, the wiring had to be drawn out of thesemiconductor device.

[0004] Therefore, in the prior art in which the area bonding can beperformed, the mounting technique is mainly based on a plating bump.Examples of such techniques include a mounting technique using a solderbump. The technique is developed by IBM Ltd. and generally called C4(Controlled Collapse Chip Connection).

[0005]FIG. 8 is a schematic cross-sectional view of a bonding structureof a semiconductor device of the above-mentioned mounting technique. AnSiO₂ film 116 is formed on a substrate 118 and an Al terminal electrode117 is formed on the SiO₂ film 116. On the terminal electrode 117, asolder bump 111 is formed via a glass protective film 115 and metalfilms 112, 113 and 114.

[0006] According to a literature “Mounting Technique of Electronics”(August (1996), pages 78-83), an aluminum oxide film is formed on thesurface of aluminum that is a material of the terminal electrode 117 ofan IC chip. After removing this oxide film, the metal films, calledbarrier metals, 112, 113 and 114 are formed by vacuum evaporation, andthen the solder bump 111 is formed. As a material for each film, forexample, a Cu—Sn intermetallic compound for the metal film 112, a Cr—Cualloy for the metal film 113 and Cr for the metal film 114 are used,respectively.

[0007] This solder bump 111 is brought into contact with an input/outputterminal electrode of a circuit board and then reflow is performed. As aresult, the solder bump 111 is melted and the bonding between the solderbump 111 and the input-output terminal of the circuit board iscompleted.

[0008] Moreover, the bump is not limited to the solder bump alone. An Auplating bump may be formed after the barrier metal is formed.

[0009] In these techniques, it is not necessary to apply load when thebump is formed. Therefore, in a case where the terminal electrode isformed on an active element of the IC chip, even if the bump is formedon the terminal electrode, the active element of the IC chip can beprevented from being damaged.

[0010] However, in these techniques, plating or treatments accompanyingthe plating are carried out. Therefore, a device for plating, a wasteliquid treatment and a washing treatment, etc. are required, thusraising the manufacturing cost. In addition, it is necessary to copewith environmental problems, separately. Consequently, it has beendifficult to put these techniques of the prior art into practical use asa consumer product.

[0011] As mentioned above, circuits of the semiconductor device havebecome finer. There was a problem in terms of securing an electrode forelectric current to flow in such finer circuits. Furthermore, in a casewhere the electroless plating is performed, it is very difficult tounify the height of the bump, so that the reliability of the mountedbody remains a problem.

SUMMARY OF THE INVENTION

[0012] It is therefore an object of the present invention to provide amanufacturing method and a mounting method for a semiconductor device,which are capable of preventing an element or wiring from beingdestroyed even if a wire bonding method is used, to provide asemiconductor device used for the above-mentioned methods, and to aninspecting method of a semiconductor device.

[0013] In order to achieve the above-mentioned object, the manufacturingmethod for a semiconductor device uses a wire bonding method using ametal wire, in the wire bonding method, an impact load applied when ametal ball formed at the tip of the metal wire by electric discharge isbrought into contact with a terminal electrode of a semiconductor deviceis smaller than a static load applied after the metal ball is broughtinto contact with the terminal electrode. With such a manufacturingmethod for the semiconductor device, by making the impact load smallerthan the static load, even when the terminal electrode is placed on anelement or wiring, the element or the wiring can be prevented from beingdamaged while securing the pressure necessary for bonding the metal ballto the terminal electrode.

[0014] It is preferable in the above-mentioned manufacturing method of asemiconductor device that the metal ball is used for forming a bump.

[0015] Furthermore, it is preferable that the metal wire is used forbonding the terminal electrode of the semiconductor device to aninput/output terminal electrode of a circuit board.

[0016] Furthermore, it is preferable that the terminal electrode isformed on an element or wiring provided inside the semiconductor device.

[0017] Furthermore, it is preferable that an ultrasonic wave is appliedat least after the static load is applied. By applying an ultrasonicwave, the bonding between the metal ball and the terminal electrode canbe stabilized.

[0018] Furthermore, it is preferable that the impact load per metal ballis 0.441 N or less, the static load is 0.981 N or less and the pressureapplied to the terminal electrode after the static load is applied is140 MPa or less.

[0019] Furthermore, it is preferable that the difference between theimpact load per metal ball and the static load is 0.736 N or less.

[0020] Furthermore, it is preferable that the metal ball is formed of atleast one metallic material selected from the group consisting of Au,Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.

[0021] Next, according to the mounting method for a semiconductor deviceof the present invention mounts a circuit board provided with a bump onan input/output terminal electrode to a semiconductor device by bondingthe tip of the bump to the terminal electrode of the semiconductordevice, wherein an impact load applied when the bump is brought intocontact with the semiconductor device is smaller than a static loadapplied after the bump is brought into contact with the terminalelectrode. With such a mounting method of the semiconductor device, bymaking the impact load smaller than the static load, even when theterminal electrode is placed on an element or the wiring, the element orwiring can be prevented from being damaged while securing the pressurenecessary for bonding the metal ball to the terminal electrode.

[0022] It is preferable in the above-mentioned mounting method that thetip of the bump has a needle shape.

[0023] Furthermore, it is preferable that the needle-shaped portioncomprises a flat portion having a diameter of 40 μm or less.

[0024] Furthermore, it is preferable that the tip of the bump has aspherical shape.

[0025] Furthermore, it is preferable that the terminal electrode of thesemiconductor device is formed on the element or the wiring providedinside the semiconductor device.

[0026] Furthermore, it is preferable that an ultrasonic wave is appliedat least after the static load is applied. By applying an ultrasonicwave, the bonding between the metal ball and the terminal electrode canbe stabilized.

[0027] Furthermore, it is preferable that the impact load per metal ballis 0.441 N or less, the static load is 0.981 N or less, and the pressureapplied to the terminal electrode after the static load is applied is140 MPa or less.

[0028] Furthermore, it is preferable that the difference between theimpact load per bump and the static load is 0.736 N or less.

[0029] Furthermore, it is preferable that the bump is formed by a wirebonding method and formed of at least one metallic material selectedfrom the group consisting of Au, Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.

[0030] Furthermore, it is preferable that the bump is formed by platingand formed of at least one metallic material selected from the groupconsisting of Au, Al, Pd, Cu, Ni, Ti, Cr and Ag.

[0031] Furthermore, it is preferable that the bump is formed by aprinting method and formed of at least one metallic material selectedfrom the group consisting of Ag, Pd, Pt, Cu, Ni, Pb, Sn and Bi.

[0032] Next, according to the inspecting method for a semiconductor ofthe present invention, the method is used for a method for manufacturinga semiconductor device by the wire bonding method using metal wire,wherein a probe needle for inspection is brought into contact with aregion on the terminal electrode other than a region in which the metalball formed at the tip of the metal wire by electric discharge is bondedto the terminal electrode. With such an inspecting method of asemiconductor device, even if the probe needle is brought into contactwith the terminal electrode and causes the loss of the terminalelectrode made of e.g. aluminum, etc., the loss is not related to theregion in which the bump is formed. Therefore, the stable bonding can berealized.

[0033] It is preferable in the above-mentioned inspecting method of asemiconductor device that the terminal electrode is formed on theelement or the wiring inside the semiconductor device.

[0034] Next, the semiconductor device of the present invention ismanufactured by the wire bonding method using a metal wire, comprising aregion with which a probe needle for inspection is brought into contact,other than the region in which the metal ball formed at the tip of themetal wire by electric discharge is bonded to the terminal electrodeformed on the semiconductor device. With such an inspecting method for asemiconductor device, even if the probe needle is brought into contactwith the terminal electrode and causes the loss of the terminalelectrode made of, e.g. aluminum, etc., the loss is not related to theregion in which the bump is formed. Therefore, the stable bonding can berealized.

[0035] It is preferable in the above-mentioned semiconductor device thatthe terminal electrode is formed on the element or the wiring providedinside the semiconductor device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1A is a schematic view showing a part of a method for forminga bump of a semiconductor device in a first embodiment according to thepresent invention.

[0037]FIG. 1B is a graph showing one example of a bonding processaccording to the present invention.

[0038]FIG. 2A is a graph showing a relationship between the static loadf, the diameter R of a seating and the height H of a seating accordingto the present invention.

[0039]FIG. 2B is a graph showing a relationship between a static load fand pressure P applied to a terminal electrode according to the presentinvention.

[0040]FIG. 2C shows a diameter of a seating according to the presentinvention.

[0041]FIG. 3A is a cross-sectional view showing a state right before animpact load is applied to a terminal electrode by wire bonding accordingto the present invention.

[0042]FIG. 3B is a cross-sectional view showing a state when a terminalelectrode is bonded to an input/output terminal electrode by a metalwire according to the present invention.

[0043]FIG. 3C is a graph showing one example of a bonding processaccording to the present invention.

[0044]FIG. 4A is a schematic cross-sectional view showing a method forinspecting a semiconductor device in a third embodiment according to thepresent invention.

[0045]FIG. 4B is a view showing one example of a square-shaped terminalelectrode seen from above in the third embodiment according to thepresent invention.

[0046]FIG. 5A is a cross-sectional view of a semiconductor device in afourth embodiment according to the present invention.

[0047]FIG. 5B is a view of a semiconductor seen from above in the fourthembodiment according to the present invention.

[0048]FIG. 6A is a schematic cross-sectional view showing a mountingprocess for a semiconductor in a fifth embodiment according to thepresent invention.

[0049]FIG. 6B is a graph showing one example of a bonding processaccording to the present invention.

[0050]FIG. 7A is a schematic cross-sectional view showing a mountingprocess of a semiconductor device in a sixth embodiment according to thepresent invention.

[0051]FIG. 7B is a graph showing one example of a bonding processaccording to the present invention.

[0052]FIG. 8 is a schematic cross-sectional view of a bonding structureof a semiconductor device of a prior art.

DETAILED DESCRIPTION OF THE INVENTION

[0053] Hereinafter, the present invention will be described by way ofembodiments with reference to drawings.

[0054] First Embodiment

[0055]FIG. 1A is a schematic view showing a part of a method for forminga bump of a semiconductor device in a first embodiment of the presentinvention. In a semiconductor device 5 shown in FIG. 1A, threeinsulating layers 4 a, 4 b and 4 c are formed on a substrate providedwith an element 3 b. In the insulating layers, wiring 3 a is formed. Onthe insulating layer 4 a, a terminal electrode 1 is formed. Morespecifically, in the semiconductor device 5 shown in FIG. 1, theterminal electrode 1 is formed on the element 3 b and the wiring 3 aprovided inside the semiconductor device 5. The terminal electrode 1 isformed primarily of, for example, aluminum. Moreover, the element 3 b isan active element such as a transistor, etc. or a passive element suchas resistance, etc.

[0056] In this embodiment, a bump is formed on the terminal electrode 1by the wire bonding method. As shown in FIG. 1A, at the tip of a metalwire 2, a metal ball 2 a is formed by electric discharge. The metal ball2 a is formed primarily of, for example, Au. However, it may be formedof at least one metallic material selected from the group consisting ofAu, Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.

[0057] The metal ball 2 a is pressed against the terminal electrode 1 bya pressure tool 6. With this embodiment, the impact load is applied tothe terminal electrode 1 when the metal ball 2 a is pressed against.After the impact load is applied, sequentially the static load isapplied. FIG. 1B shows one example of the bonding process. T of theabscissa shows time, F of the ordinate shows the magnitude of the loadand t1 in FIG. 1B shows a time in which an ultrasonic wave is applied(the same is true in the following FIGS. 2C, 5B and 6B). In the exampleof this figure, the load per metal ball is 0.245 N (25 gram weight) forthe impact load as shown by the remark 5 and 0.392 N (40 gram weight)for the static load as shown by the remark 6.

[0058] Main constituent factors related to the impact load include thespeed when the metal ball is brought into contact with the terminalelectrode, a detection load that is a reference with which the devicedetects that the metal ball is brought into contact with the terminalelectrode, the size of the metal ball, and the like. In order to reducethe impact load, the speed is preferably small. Furthermore, thedetection load is preferably small because load is applied until theload reaches to the reference load. In addition, as to the metal ball,especially for an Au ball that is soft, the larger the Au ball is, thegreater the effect of relaxing the impact is. Therefore, it ispreferable that the Au ball is large. After the impact load is applied,the static load is applied so as to stabilize the bonding property ofthe metal ball. In general, it is preferable that an ultrasonic wave isused together in order to secure the stability.

[0059] Herein, a state right after the metal ball 2 a made of Au, etc.is brought into contact with the terminal electrode 1 is described.Until the metal ball 2 a is sufficiently crushed, the contact areabetween the metal ball 2 a and the terminal electrode 1 is small.Therefore, stress is tends to be concentrated on the contact portion,and thus a high pressure is applied thereto. Therefore, by reducing theimpact load, the element 3 b or the wiring 3 a placed below the terminalelectrode 1 can be prevented from being damaged. The load for bondingcan be secured by making the static load applied after the impact loadis applied larger than the impact load. When the impact load is applied,the metal ball 2 a is sufficiently crushed. Therefore, even if thestatic load is increased, the pressure applied to the terminal electrode1 can be reduced such that damage to the element 3 b or the wiring 3 aplaced below the terminal electrode 1 can be prevented. Moreover, thedamage herein denotes the deterioration of the property, the electriccurrent leak due to the occurrence of cracks, or the like.

[0060] In other words, according to this embodiment, by making theimpact load smaller than the static load, even if the terminal electrodeis placed on the element or the wiring, the element or the wiring can beprevented from being damaged while securing the pressure necessary forbonding. Furthermore, since the technique of this embodiment does notrequire a washing process, the cost can be reduced. Further, it is notnecessary to cope especially with environmental problems. Furthermore,since bonding to the terminal electrode on the element or the wiring ispossible, the terminal electrode is not required to be formed outsidethe element or the wiring to thus enable a miniaturization of thedevice. Furthermore, since the wiring is not required to be drawn out ofthe device, the cost can be reduced and higher performance can berealized.

[0061] Hereinafter, this embodiment will be explained more specificallyby way of the experiment results. Table 1 shows the conditions forbonding the Au ball to the terminal electrode. These conditions can beused for forming the bump and for performing the wire bonding method.TABLE 1 Time for Stage Detec- Output of applying Ball tem- Search tionStatic ultrasonic ultrasonic size pera- Con- speed load load wave wave(μm ture dition (mm/s) (N) (N) (mW) (msec) φ) (° C.) (A)  5 0.441 0.294100 20 50 230 (B) 15 0.588 0.392 100 20 50 230 (C) 30 0.981 0.981 100 2050 230 (D)  5 0.441 0.294 200 20 50 230

[0062] The impact load depends upon the speed when the Au ball isbrought into contact with the terminal electrode (hereinafter, “searchspeed” will be referred to) and the detection load. When the searchspeed is large, even if the device detects the detection load, thecontrol for inhibiting the load does not follow. Therefore, actually,load greater than the detection load is applied to the terminalelectrode. In this case, the load greater than the detection load is animpact load. When the impact load is actually measured under theconditions (A), (B) and (C) of Table 1, the measurement results shown inTable 2 were obtained. TABLE 2 Condition (A) (B) (C) Impact load 0.441 N0.735 N 1.961 N

[0063] The impact load shown in Table 2 was measured by using a pressuresensor. As shown in Table 2, as in the conditions (A) where the searchspeed is as relatively low as 5 mm/s, the impact load is equal to thedetection load. On the contrary, as in the condition (C) where thesearch speed is as high as 30 mm/s, the detection load is 0.981 N (100gram weight) while the actual impact load is 1.961 N (200 gram weight)that is much larger than the detection load.

[0064] Table 3 shows the results of qualities evaluated under theconditions (A) to (D) of Table 1. TABLE 3 Condition (A) (B) (C) (D) Alwiring leak 0/192 0/192 1/64 0/128 Nch MOS Tr 0/54  3/54  — 2/54 property deterioration

[0065] The “Al wiring leak” of the measurement item of Table 3 showsresults of whether or not the electric current leak occurs due to theoccurrence of cracks by bonding between the Al wiring 3 a and theterminal electrode 1 (the distance between them: 1 μm). The insulatinglayer is an SiO₂ layer.

[0066] Another measurement item, “Nch MOS Tr property deterioration”shows results of whether or not the deterioration of the threshold valueor electric current leak occurs due to the bonding when the terminalelectrode is placed on the Nch MOS transistor. The insulating layer isan SiO₂ layer. Moreover, the distance between the terminal electrode andthe Nch MOS transistor is 4.97 μm. Among the written numerical values inTable 3, the numerical values of the right side show the number ofsamples and those of the left side show the number of defectives.

[0067] The results in Table 3 show that even if the static load issmall, if the impact load per bump is 0.735 N (75 gram weight) or more,the property deterioration is easily caused by the stress concentration(conditions (B) and (C)). Furthermore, Table 3 also shows that in therange where the impact load is up to 0.441 N (45 gram weight), there isno problem (condition (A)).

[0068] Furthermore, the comparison between the condition (A) and thecondition (B) shows that the effect by the energy propagation by theultrasonic wave is not negligible. Therefore, it is preferable thatultrasonic wave is used at the energy of 100 mW or less and for about 20msec.

[0069] Next, other experiment results are shown. They are obtained whenexperiments were carried out while changing conditions. Table 4 showsthe bonding conditions. TABLE 4 Output Time for Stage Detec- of ultra-applying Ball tem- Search tion Static sonic ultrasonic size pera- Con-speed load load wave wave (μm ture dition (mm/s) (N) (N) (mW) (msec) φ)(° C.) (E)  5 0.196 0.294 60 20 52˜55 260 (F) 15 0.490 0.392 85 20 52˜55260 (G) 20 0.588 0.392 85 20 52˜55 260 (H) 50 0.981 0.981 85 20 52˜55260

[0070] Table 5 shows the results of qualities evaluated under theconditions (H) of Table 4. TABLE 5 Condition (E) (F) (G) (H) Al wiringleak 0/320 0/320 0/320 3/30

[0071] As shown in the results of Table 5, defectives occurred onlyunder the condition (H). Herein, the condition (G) is similar to thecondition (B). Consequently, it is shown that when the impact load isreduced to some extent, the occurrence of defectives can be inhibited.

[0072] Next, the experiment results are shown with respect to thevarious of devices. Table 6 shows the results when the bonding wasperformed in a case where the terminal electrode is formed on the NchMOS transistor. TABLE 6 [The terminal electrode is formed on an Nch MOStransistor.] Search Stage Output of Change of speed temperature Staticload ultrasonic threshold (mm/s) (° C.) (N/bump) wave (mW) voltage 1  5330 0.049˜0.981 40 1.0% or less 2 10 330 0.196˜0.392 40 1.2% or less 320 330 0.196˜0.392 40 1.0% or less 4 20 200 0.196˜0.392 40 1.2% or less5 20 150 0.196˜0.981 40˜100 0.6% or less

[0073] Table 7 shows the results when the bonding was performed in acase where the terminal electrode is provided on a Pch MOS transistor.TABLE 7 [The terminal electrode is formed on the Pch MOS transistor.]Search Stage Output of Change of speed temperature Static loadultrasonic threshold (mm/s) (° C.) (N/bump) wave (mW) voltage 6 5 3300.049˜0.588 40 0.3% or less

[0074] Table 8 shows the results when the bonding was performed in acase where the terminal electrode is provided on a SRAM transistor.TABLE 8 [The terminal electrode is provided on a SRAM transistor.]Search Stage Output of speed temperature Static load ultrasonic (mm/s)(° C.) (N/bump) wave (mW) Bit error 7 5 330 0.049˜0.588 40 0/228

[0075] Table 9 shows the results when the bonding was performed in acase where the terminal electrode is provided on the Al wiring. TABLE 9[The terminal electrode is provided on Al wiring.] Search Stage Outputof Electric speed temperature Static load ultrasonic current (mm/s) (°C.) (N/bump) wave (mW) leak  8  5 330 0.049˜0.392 40 Each 0/82  9 10 3300.196˜0.392 40 Each 0/16 10 20 330 0.196˜0.392 40 Each 0/16 11 20 2000.196˜0.392 40 Each 0/16 12 20 150 0.196˜0.981 40˜100 Each 0/16

[0076] When the terminal electrode is formed on the element, thedistance between the terminal electrode and the element is 4.97 μm. Whenthe terminal electrode is formed on the Al wiring, the distance betweenthe terminal electrode and the Al wiring is 1 μm.

[0077] The conditions common to the experiments shown in Tables 6 to 9include: the detection load per bump of 0.245 N (25 gram weight); thetime of applying ultrasonic wave of 15 msec; and the diameter of the Auball of about 69 μm. In all cases, an ultrasonic wave is applied at thesame time the static load is applied. Moreover, there is no problem aslong as the ultrasonic wave is applied at least after the static load isapplied.

[0078] As is apparent from the results of Tables 6 to 9, all sampleshave no property deterioration or no electric current leak, showing theexcellent results. More specifically, if the static load is inhibited tosome extent, there arises no problems even if the static load per bumpthat is applied after the impact load is applied is 0.981 N (100 gramweight) and the ultrasonic wave is 100 mW.

[0079] Next, the shape of the bump and pressure applied to the terminalelectrode were measured while changing the static load. The measurementresults are described as follows. The measurement conditions are shownin Table 10. TABLE 10 Output Stage Detec- of ultra- Time of Ball tem-Search tion Static sonic applying size pera- Con- speed load load wavewave (μm ture dition (mm/s) (N) (N) (mW) (msec) φ) (° C.) 5 0.245 0.245˜40 20 about 330 1.373 69

[0080] The lower part of the bump, which was obtained after the Au ballwas deformed and the static load was applied thereto, is referred to asa seating. FIG. 2A is a graph showing a relationship between the staticload f, the diameter R of the seating and the height H of the seating.FIG. 2B is a graph showing a relationship between the static load f andthe pressure P applied to the terminal electrode. The pressure appliedto the terminal electrode can be calculated from the area of the seatingand the static load. More specifically, as shown in FIG. 2C, the averagediameter R of the seating is expressed by the following equation (1) andthe average radius r of the seating is expressed by the followingequation (2). In the equations (1) and (2), φx and φy denote diametersof the seating, respectively.

R=(φx+φy)/2  equation (1)

r=R/2  equation (2)

[0081] When the pressure P is expressed by the following equation (3):

P=f/πr ²  equation (3)

[0082] wherein f denotes the static load and P denotes the pressureapplied to the terminal electrode.

[0083] It is preferable that the pressure applied to the terminalelectrode after the static load is applied is up to 140 MPacorresponding to the pressure when the static load per bump is 0.981 N(100 gram weight).

[0084] As mentioned in the experiment results, it is preferable that thedevice is used under the conditions of: the impact load per bump of0.441 N (45 gram weight) or less, the static load of 0.981 N (100 gramweight) or less; the ultrasonic wave of 100 mW or less; and the pressureapplied to the terminal electrode after the static load is applied of upto 140 MPa corresponding to the pressure when the static load per bumpis 0.981 N (100 gram weight). Furthermore, there is no problem as longas the impact load is secured to be 0.245 N (25 gram weight). Asmentioned above, it is preferable that the impact load is 0.981 N orless. Therefore, it is preferable that the difference between the impactload per metal ball and the static load is 0.736 N (75 gram weight).

[0085] Second Embodiment

[0086]FIGS. 3A and B are schematic views showing a bonding process whenwire bonding is performed on a terminal electrode of a semiconductordevice. In a semiconductor device 25 shown in FIG. 3A, three insulatinglayers 24 a, 24 b and 24 c are formed on a substrate provided with anelement 23 b. In the insulating layers, wiring 23 a is formed. On theinsulating layer 24 a, a terminal electrode 21 is formed. Morespecifically, in the semiconductor device 25 shown in FIG. 3, theterminal electrode 21 is formed on the element 23 b and the wiring 23 aprovided inside the semiconductor device 25. The terminal electrode 21is formed primarily by, for example, aluminum. Furthermore, the element23 b is an active element such as a transistor, etc. or a passiveelement such as resistance, etc.

[0087] As shown in FIG. 3A, at the tip of a metal wire 22, a metal ball22 a is formed by electric discharge. The metal ball 22 a is formedprimarily of, for example, Au. However, it may be formed of at least onemetallic material selected from the group consisting of Au, Al, Pd, Pb,Sn, Cu, In, Bi, Ti and Ni.

[0088] The metal ball 22 a is pressed against the terminal electrode 21by a pressure tool 6. With this embodiment, the impact load is appliedto the terminal electrode 21 when the metal ball 22 a is pressedagainst, and sequentially the static electrode is applied. FIG. 3C showsone example of the bonding process. In the example of this figure, theload per metal ball is 0.245 N (25 gram weight) for the impact load asshown by the remark 25 and 0.392 N (40 gram weight) for the static loadas shown by the remark 26.

[0089] Also in this embodiment, for the same reason as in the firstembodiment, the impact load is set to be smaller than the static load,whereby the element 23 b or the wiring 23 a placed below the terminalelectrode 21 can be prevented from being damaged. Furthermore, it isgenerally preferable that an ultrasonic wave is used together in orderto secure the stability. Herein, the damage denotes the deterioration ofproperty, the electric current leak due to the occurrence of cracks, orthe like.

[0090] Furthermore, as shown in FIG. 3B, the tip opposed to the metalball 22 a of the metal wire 22 is bonded to an input/output terminalelectrode 28 of the circuit board 27.

[0091] Similar to the first embodiment, also in the second embodiment,it is preferable that the device is used under the conditions of: theimpact load per bump of 0.441 N (45 gram weight) or less; the staticload of 0.981 N (100 gram weight) or less; ultrasonic wave of 100 mW orless; and the pressure applied to the terminal electrode after thestatic load is applied of up to 140 MPa corresponding to the pressurewhen the static load per bump is 0.981 N (100 gram weight). Furthermore,there is no problem as long as the impact load is secured to be 0.245 N(25 gram weight). As mentioned above, it is preferable that the impactload is 0.981 N or less. Therefore, it is preferable that the differencebetween the impact load per metal ball and the static load is 0.736 N(75 gram weight).

[0092] Third Embodiment

[0093] The third embodiment of the present invention relates to a methodfor inspecting a semiconductor device. FIG. 4 is a schematic viewshowing a method for inspecting a semiconductor device of thisembodiment. FIG. 4A is a cross-sectional view of a semiconductor device,and FIG. 4B is a view of a semiconductor device seen from above.

[0094] In a semiconductor device 37 shown in FIG. 4A, three insulatinglayers 34 a, 34 b and 34 c are formed on a substrate provided with anelement 33 b. In the insulating layers, wiring 33 a is formed. On theinsulating layer 34 a, a terminal electrode 31 is formed. Morespecifically, in the semiconductor device 37, the terminal electrode 31is formed on the element 33 b and the wiring 33 a provided inside thesemiconductor device 37.

[0095]FIG. 4A shows a state before the wire bonding is carried out onthe terminal electrode 31 or before the bump is formed by the wirebonding method.

[0096]FIG. 4B shows an example of the terminal electrode 31 having asquare shape that is a general shape of the terminal electrode. However,the shape of the terminal electrode is not limited to a square shapealone. The terminal electrode 31 is formed primarily of aluminum. Thehatched part of the terminal electrode 31 shows the region in which themetal ball is bonded.

[0097] Since a bonding region 35 of the metal ball is thought to besimilar to a circular shape, the corner region 36 of the terminalelectrode 31 is a region that is not related to the bonding. If thebonding region 35 of the metal ball is inspected by bringing a probeneedle 32 into contact with the bonding region 35 in advance, the lossof aluminum occurs because of the contact. When the bonding is performedlater, an intermetallic compound of the metal ball and the terminalelectrode (primarily aluminum) is generated, thus inhibiting thestability of the bonding.

[0098] In this embodiment, the region in which the probe needle 32 forinspection is in contact with a corner region 36 of the terminalelectrode 31, which is not related to the bonding region 35 of the metalball. Therefore, in the bonding region 35, there is no loss of aluminumcaused by the contact of the prove needle 32, thus enabling the stablebonding connection.

[0099] Fourth Embodiment

[0100] The fourth embodiment of the present invention relates to asemiconductor device suitable for the inspection when the wire bondingis carried out or the bump is formed by the wire bonding method. FIG. 5Ais a cross-sectional view of a semiconductor device according to thisembodiment; and FIG. 5B is a view of a semiconductor seen from above.

[0101] In a semiconductor device 47 shown in FIG. 5A, three insulatinglayers 44 a, 44 b and 44 c are formed on a substrate provided with anelement 43 b. In the insulating layers, the wiring 43 a is formed. Onthe insulating layer 44 a, a terminal electrode 41 is formed. Morespecifically, in the semiconductor device 47, the terminal electrode 41is formed on the element 43 b and the wiring 43 a provided inside thesemiconductor device 47.

[0102]FIG. 5A shows a state before the wire bonding is carried out onthe terminal electrode 41 or before the bump is formed by the wirebonding method. FIG. 5B shows an example of the terminal electrode 41having a rectangular shape. The terminal electrode 41 is formedprimarily of aluminum. The bonding region 45 shown by a hatched part ofthe terminal electrode 41 shows the region in which the metal ball isbonded. A bonding region of the metal ball is thought to be similar to acircular shape.

[0103] In this embodiment, an inspection region 46 is provided on theterminal electrode 41. When the probe needle 42 is brought into contactwith the bonding region 45 of the metal ball in advance, the loss ofaluminum occurs due to the contact. When the bonding is performed later,an intermetallic compound is generated between the metal ball and theterminal electrode (primarily aluminum), thus inhibiting the stabilityof the bonding.

[0104] In this embodiment, the contact region of the probe needle 42 isprovided separately from the bonding region 45 of the metal ball.Therefore, the stable bonding connection is possible.

[0105] Fifth Embodiment

[0106]FIG. 6A is a schematic view showing a mounting process for asemiconductor according to a fifth embodiment of the present invention.In a semiconductor device 59 shown in FIG. 6A, three insulating layers54 a, 54 b and 54 c are formed on a substrate provided with an element53 b. In the insulating layers, wiring 53 a is formed. On the insulatinglayer 54 a, a terminal electrode 51 is formed. More specifically, in thesemiconductor device 59, the terminal electrode 51 is formed on theelement 53 b and the wiring 53 a provided inside the semiconductordevice 59. The element 53 b is an active element such as a transistor,etc. or a passive element such as resistance, etc.

[0107] On an input/output terminal electrode 58 of a circuit board 57shown in FIG. 6A, a bump 52 having a needle-shaped tip is formed. Thebump 52 is bonded to the terminal electrode 51 of the semiconductorelectrode 59. The bump 52 can be formed in a shape of a needle having adiameter of a tip flat portion of 40 μm or less on the input/outputterminal electrode 58 of the circuit board 57 by, for example, the wirebonding method.

[0108] It is preferable that when the bump 52 is formed by the wirebonding method, it is formed of at least one metallic material selectedfrom the group consisting of Au, Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.It is further preferable that when the bump 52 is formed by plating, itis formed of at least one metallic material selected from the groupconsisting of Au, Al, Pd, Cu, Ni, Ti, Cr and Ag. It is still furtherpreferable that when the bump 52 is formed by a printing method, it isformed of at least one metallic material selected from the groupconsisting of Ag, Pd, Pt, Cu, Ni, Pb, Sn and Bi.

[0109] The circuit board 57 moves in the direction shown by the arrow inFIG. 6A, and then the bump 52 is pressed against the terminal electrode51. Consequently, the impact load is applied to the terminal electrode51 when the bump 52 is pressed. After the impact load is applied,sequentially the static load is applied. FIG. 6B shows one example ofthe bonding process. In the example of this figure, the load per metalball is 0.245 N (25 gram weight) for the impact load as shown by theremark 55 and 0.392 N (40 gram weight) for the static load as shown bythe remark 56.

[0110] Main constituents factors related to the impact load include thespeed when the metal ball is brought into contact with the terminalelectrode, the detection load that is a reference with which the devicedetects that the metal ball is brought into contact with the terminalelectrode, the size of the metal ball, and the like. In order to reducethe impact load, the speed is preferably small. Furthermore, thedetection load is preferably small because the load is applied until theload reaches to a target load.

[0111] Furthermore, as to the flat portion at the tip of the bump, thelarger the flat portion is, the smaller the stress is. Therefore, theflat portion at the tip is preferably large. More specifically, it ispreferable that the diameter of the flat portion is as large as possiblein the range of 40 μm or less.

[0112] After the impact load is applied, the static load is applied soas to stabilize the bonding property of the bump. In general, it ispreferable that the ultrasonic wave is used together in order to securethe stability.

[0113] This mounting process can be employed in any mounting methodsthat require pressure. For example, it may be employed in the case wherethe ultrasonic wave is used together to perform a pressure welding thebump. Furthermore, it may be employed in the mounting via a connectinglayer such as conductive paste, an anisotropic conductive film, etc.

[0114] Herein, the state right after the bump 52 is brought into contactwith the terminal electrode 51 is described. Until the bump 52 issufficiently crushed, the contact area between the bump 52 and theterminal electrode 51 is small. Therefore, stress tends to beconcentrated on the contact portion, and thus a high pressure is appliedthereto. Therefore, by reducing the impact load, the element 53 b or thewiring 53 a placed below the terminal electrode 51 can be prevented frombeing damaged. The load for bonding can be secured by making the staticload applied after the impact load is applied larger than the impactload. When the impact load is applied, the bump 52 is sufficientlycrushed, even if the static load is increased, the pressure applied tothe terminal electrode 51 can be reduced such that damage to the element53 b or the wiring 53 a placed below the terminal electrode 51 can beprevented. Herein, the damage denotes the deterioration of the property,the electric current leak due to the occurrence of cracks, or the like.

[0115] Furthermore, in the mounting process according to thisembodiment, the experiment results described in the first embodiment canbe employed. Therefore, it is preferable that the impact load per bumpis 0.441 N (45 gram weight) or less, the static load is 0.981 N (100gram weight) or less; the ultrasonic wave is 100 mW or less; and thepressure applied to the terminal electrode after the static load isapplied is up to 140 MPa corresponding to the pressure when the staticload per bump is 0.981 N (100 gram weight). Furthermore, there is noproblem as long as the impact load is secured to be 0.245 N (25 gramweight). As mentioned above, it is preferable that the impact load is0.981 N or less. Therefore, it is preferable that the difference betweenthe impact load per metal ball and the static load is 0.736 N (75 gramweight).

[0116] Sixth Embodiment

[0117]FIG. 7A is a schematic view showing a mounting process for asemiconductor device according to a sixth embodiment of the presentinvention. In a semiconductor device 69 shown in FIG. 7A, threeinsulating layers 64 a, 64 b and 64 c are formed on a substrate providedwith an element 63 b. In the insulating layers, wiring 63 a is formed.On the insulating layer 64 a, a terminal electrode 61 is formed. Morespecifically, in the semiconductor device 69, the terminal electrode 61is formed on the element 63 b and the wiring 63 a provided inside thesemiconductor device 69. The element 63 b is an active element such as atransistor, etc. or a passive element such as resistance, etc.

[0118] The sixth embodiment is different from the fifth embodiment inthat the bump 62 has a spherical-shaped tip. Such a bump 62 having aspherical-shaped tip can be formed by, for example, plating. Thematerial of the bump 62 is the same as that in the fifth embodiment.

[0119] The method for mounting the semiconductor device 69 to thecircuit board 67 in this embodiment is the same as that of the fifthembodiment. In other words, also in this embodiment, by making theimpact load smaller than the static load, damage to the element 63 b orthe wiring 63 a placed below the terminal electrode 61 can be prevented.

[0120]FIG. 7B shows one example of the bonding process. In the exampleof this figure, the load per bump is 0.245 N (25 gram weight) for theimpact load as shown by the remark 65 and 0.392 N (40 gram weight) forthe static load as shown by the remark 66.

[0121] Furthermore, also in the mounting process according to thisembodiment, the experiment results described in the first embodiment cansimilarly be employed. Therefore, as mentioned in the experimentresults, it is preferable that the device is used under the conditionsof: the impact load per bump of 0.441 N (45 gram weight) or less, thestatic load of 0.981 N (100 gram weight) or less; ultrasonic wave of 100mW or less; and the pressure applied to the terminal electrode after thestatic load is applied of up to 140 MPa corresponding to the pressurewhen the static load per bump is 0.981 N (100 gram weight). Furthermore,there is no problem as long as the impact load is secured to be 0.245 N(25 gram weight). As mentioned above, it is preferable that the impactload is 0.981 N or less. Therefore, it is preferable that the differencebetween the impact load per metal ball and the static load is 0.736 N(75 gram weight).

[0122] The invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Theembodiments disclosed in this application are to be considered in allrespects as illustrative and not restrictive, the scope of the inventionis indicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

What is claimed is:
 1. A manufacturing method for a semiconductor deviceusing a wire bonding method using a metal wire, wherein in said wirebonding method, an impact load applied when a metal ball formed at thetip of said metal wire by electric discharge is brought into contactwith a terminal electrode of a semiconductor device is smaller than astatic load applied after said metal ball is brought into contact withsaid terminal electrode.
 2. The method for manufacturing a semiconductordevice according to claim 1 , wherein said metal ball is used forforming a bump.
 3. The method for manufacturing a semiconductor deviceaccording to claim 1 , wherein said metal wire is used for bonding theterminal electrode of the semiconductor device to an input/outputterminal electrode of a circuit board.
 4. The method for manufacturing asemiconductor device according to claim 1 , wherein said terminalelectrode is formed on an element or wiring provided inside saidsemiconductor device.
 5. The method for manufacturing a semiconductordevice according to claim 1 , wherein an ultrasonic wave is applied atleast after said static load is applied.
 6. The method for manufacturinga semiconductor device according to claim 1 , wherein the impact loadper said metal ball is 0.441 N or less, the static load is 0.981 N orless and the pressure applied to said terminal electrode after saidstatic load is applied is 140 MPa or less.
 7. The method formanufacturing a semiconductor device according to claim 1 , wherein thedifference between the impact load per said metal ball and said staticload is 0.736 N or less.
 8. The method for manufacturing a semiconductordevice according to claim 1 , wherein said metal ball is formed of atleast one metallic material selected from the group consisting of Au,Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.
 9. A method for mounting asemiconductor device, comprising mounting a circuit board provided witha bump on an input/output terminal electrode to a semiconductor deviceby bonding the tip of said bump to said terminal electrode of saidsemiconductor device, wherein an impact load applied when said bump isbrought into contact with said semiconductor device is smaller than astatic load applied after said bump is brought into contact with saidterminal electrode.
 10. The method for mounting a semiconductor deviceaccording to claim 9 , wherein the tip of said bump has a needle shape.11. The method for mounting a semiconductor device according to claim 10, wherein said needle-shaped portion comprises a flat portion having adiameter of 40 μm or less.
 12. The method for mounting a semiconductordevice according to claim 9 , wherein the tip of said bump has aspherical shape.
 13. The method for mounting a semiconductor deviceaccording to claim 9 , wherein the terminal electrode of saidsemiconductor device is formed on the element or the wiring providedinside said semiconductor device.
 14. The method for mounting asemiconductor device according to claim 9 , wherein an ultrasonic waveis applied at least after said static load is applied.
 15. The methodfor mounting a semiconductor device according to claim 9 , wherein theimpact load per said bump is 0.441 N or less, the static load is 0.981 Nor less, the pressure applied to said terminal electrode after saidstatic load is applied is 140 MPa or less.
 16. The method for mounting asemiconductor device according to claim 9 , wherein the differencebetween the impact load per said bump and said static load is 0.736 N orless.
 17. The method for mounting a semiconductor device according toclaim 9 , wherein said bump is formed by a wire bonding method andformed of at least one metallic material selected from the groupconsisting of Au, Al, Pd, Pb, Sn, Cu, In, Bi, Ti and Ni.
 18. The methodfor mounting a semiconductor device according to claim 9 , wherein saidbump is formed by plating and formed of at least one metallic materialselected from the group consisting of Au, Al, Pd, Cu, Ni, Ti, Cr and Ag.19. The method for mounting semiconductor electrode according to claim 9, wherein said bump is formed by a printing method and formed of atleast one metallic material selected from the group consisting of Ag,Pd, Pt, Cu, Ni, Pb, Sn and Bi.
 20. A method for inspecting asemiconductor device used for a method for manufacturing a semiconductordevice by a wire bonding method using metal wire, wherein a probe needlefor inspection is brought into contact with a region on said terminalelectrode other than a region in which the metal ball formed at the tipof said metal wire by electric discharge is bonded to said terminalelectrode among regions on the terminal electrode of the semiconductordevice.
 21. The method for inspecting a semiconductor device accordingto claim 20 , wherein said terminal electrode is formed on the elementor the wiring provided inside said semiconductor device.
 22. Asemiconductor device manufactured by a wire bonding method using a metalwire, comprising a region with which a probe needle for inspection isbrought into contact in addition to a region in which the metal ballformed at the tip of said metal wire by electric discharge is bonded tosaid terminal electrode formed on the semiconductor device.
 23. Thesemiconductor device according to claim 22 , wherein said terminalelectrode is formed on the element or the wiring inside saidsemiconductor device.